Verapamil, a calcium antagonist, was found to improve exercise capacity relative to placebo and subjective symptomatic status in a group of patients with hypertrophic cardiomyopathy, the majority of whom were medical failures with propranolol. The effect of verapamil on exercise capacity was similar to that of propranolol, but verapamil appeared to provide more subjective symptomatic benefit than propranolol.